One sexual activity that is around but not exactly mainstream is fisting. What exactly is fisting you ask, in case you are unaware of this? It’s where one partner inserts their entire hand, sometimes more all the way either into the vagina or the anus. Some of the pics online are unreal, some are in all the way up the elbows and even up to the shoulder, they look like they are about to examine a cow in labor or something!
Personally I can’t understand the appeal of such an act, it looks painful for one, seems medical in nature, but then some are into medical type fetishes, but there’s no shortage of fisting porn out there for ones that look for it. Popular in gay culture and spreading outward, it continues to be viewed as extreme by some. Some insert with the fist balled up, others point all their fingers into a duck like bill of sorts to make insertion easier for the one being fisted.
Gloves are recommended for this activity as the anal tissues are so easily damaged and not self lubricating like a vagina, that tiny tears could result leading to higher chances of infection. As porn becomes more mainstream, ones that consume it do often seek more and more extreme stimulation, and this might be just the activity they would experiment with once they have tried others that used to be considered on the fringes, like anal sex, rimming, the acts escalate for many, always seeking that higher level of pleasure.